Cobble/small boulder debris device in borehole excavating

ABSTRACT

A cobble and small boulder debris removal device including a quiescently open 3 prong claw, and a series of springs and cables within or affixed to a shaft to close the prongs in gripping and holding such cobbles when encountered in the pre-clearance of a borehole, to be then removed by being lifted away and released via a relaxation of a lever connected with a main actuating cable.

CROSS-REFERENCE TO RELATED APPLICATIONS

NONE

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Research and development of this invention and Application have not been federally sponsored, and no rights are given under any Federal program.

REFERENCE TO A MICROFICHE APPENDIX

NOT APPLICABLE

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to drilling of boreholes for installing a monitoring well or for obtaining a core sample, in general, and to a device for the below-grade removal of rock and small boulder debris in borehole drillings, in particular.

2. Description of the Related Art

As will be appreciated, State environmental laws require the periodic inspection of automotive service stations to ensure that no contamination of groundwater exists as a result of leakage of gasoline or diesel fuel from their underground storage tanks, pipings and pumping islands. As will also be appreciated, these stations suffer not only site-specific restraints from their typically ¼-½ acres in size, but also by being crossed with such subsurface utilities as electric lines, sewer lines, telephone lines and water lines. Monitoring wells for these inspections, therefore, must be accurately located.

Over time, protocols for clearing these below-grade wells have been developed both by the environmental agencies and by the service station responsible parties. Usually, the protocols involve a telephone contact of the utility companies and/or investigation of marked indicia to determine the subsurface line positioning at the area in question. “Soft-dig” techniques then follow, in slowly loosening the soil to confirm a clearance of the utility lines. Once a position is satisfactorily determined, the protocols might be such as: a) if the installation is to be less than 10 feet measured horizontally from the utility line, a minimum drilling depth to 8 feet below grade is to be followed; b) if the distance from the utility line measured horizontally is greater than 10 feet, then a borehole drilling depth to a minimum of 5 feet might be the one required; or c) if the installation is to be less than 10 feet from an underground storage tank, from its fuel lines to the dispensing islands, to the pumps, to the pipes, vents, vent holes, electrical lines and like appurtenances utilized), then a borehole depth might be required to a minimum depth of 10 feet below grade.

As will be understood by those skilled in the art, these boreholes are frequently started with shovels and post-hole diggers. With a vacuum excavator, and then a drill auger, the borehole is usually cleared not only to the required depth, but of a diameter at least 4 inches greater than that of the drill bit itself. Truck mounted equipments are often employed in these manners in removing the soil, gravel and rocks as the drilling proceeds. When drilling these monitoring wells at service station properties, however, it is not unusual to find beneath the asphalt surface pieces of wood, used tires, and other debris which is not so easily sucked up by a truck mounted vacuum excavator. But, even where such type of “urban fill” is not present, it is typical to come upon rocks and small boulders (denoted as “cobbles”) which are too large to be sucked up by vacuum excavation. Insufficient space exists for shovels and post-hole diggers to get down to remove these types of interferences manually—for example, as when attempting to drill an 18″-20″ diameter hole to a depth of 8′ at a location spaced 5′-6′ from a subsurface water line. Then, either a more powerful vacuum excavator needs to be brought to the site in an attempt to dislodge the rock or boulder, or the borehole is filled back up. In this latter event, a move to a different location might be in order, and the time and effort of proceeding to that point would be wasted, with its attendant non-productive cost.

(In this respect, in the description that follows, the term “cobble” will be used to refer to a rock or small boulder in size from 2″ to 10″ in diameter, with anything larger than 10″ being referred to simply as a “boulder”, and with anything smaller than 2″ being referred to simply as a “pebble”.) As will be appreciated, this problem brought on by the presence of “cobbles” is not just limited to the installation of monitoring wells at automotive service stations, but exists also wherever a core sample is to be taken from a prescribed subsurface depth.

OBJECTS OF THE INVENTION

It is an object of the present invention, therefore, to provide a new and improved tool for removing “cobbles” from pre-cleared boreholes ranging to depths of 10′.

It is an object of the present invention, also, to provide such a tool which can be used with relative ease by one person acting alone, in removing “cobbles” that are difficult to remove by commonly used truck-mounted vacuum excavators.

It is another object of the invention, to provide such a tool which significantly lessens the bending and lifting efforts otherwise required to remove “cobble-size” rocks and small boulders from boreholes.

It is yet a further object of the invention to provide this tool so as to reduce the number of variance requests that might otherwise be sought in not clearing a borehole to its required protocol-established depth.

And, it is a primary object of the invention to provide this tool of a weight light enough to be manageable by an operator utilizing one hand, and allowing the opposite hand to be used to remove “softball” to “soccerball/football” sized “cobbles” in such borehole excavating.

SUMMARY OF THE INVENTION

As will become clear from the following description of the present invention, the rock and small boulder debris removal device includes a quiescently open 3 prong claw, and a series of springs and cables within or affixed to a shaft to close the prongs to then grip and hold such cobbles when encountered in the “pre-clearing” or “soft-digging” of boreholes prior to inserting drilling tools and permanent/non permanent features. Such rocks and small boulders are then removed by the device being lifted out and away from the borehole, and then through a manual releasing of a lever connected with a main actuating cable, the cobble is released.

In a preferred embodiment, a shaft is provided enclosing first, second and third cables, each of which is individually connected at one end with one prong of the 3 prong claw. First, second and third springs are further included, each individually connecting one of the prongs to angularly spaced locations on an external surface of the shaft. A one-to-three cable transition coupler is situated within the shaft having an input connected to a first end of a fourth spring within the shaft and an output connected to respective second ends of the first, second and third cables. An operating lever is employed outside of the shaft, and a fourth cable connects the operating lever to a second end of the fourth spring. As so constructed, a user rotation of the operating lever in a first direction pulls upon the fourth cable to close the claw, and a release of the operating lever relaxes the fourth cable to return the claw to its quiescently open condition.

In this preferred embodiment, a 5 foot to 10 foot long shaft is utilized, with the component shaft, claw and lever fabricated of any ridged material. The operating lever is manually controlled by a workman at the job site.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the present invention will be more clearly understood from a consideration of the following description, taken in connection with the accompanying drawings, in which:

FIG. 1 is a schematic diagram helpful in an understanding of the interplay between the 3 prong claw, the shaft components and the operating lever of the invention in removing cobbles and small boulder debris from a borehole;

FIGS. 2, 3 and 4 are helpful in an understanding of the positioning of the 3 prong claw in its open and closed positions; and

FIGS. 5 a and 5 b are helpful in an understanding of the operating lever control of the prong claw by a user thereof.

DETAILED DESCRIPTION OF THE INVENTION

The cobble removal device of the invention schematically shown in FIG. 1 includes a hollow shaft 10 fabricated of steel or light weight ridged material and of a length typically between 5-10 feet in satisfying the protocols for use when conducting pre-clearing or soft-dig activities where necessary the teachings of the invention apply, in general, to any needed length). Within the shaft 10 is a first spring 12, joined at its end terminals A and B with a main cable 14 (of 3/16″ diameter steel, for example). That length of the cable connected to spring terminal A extends outwardly through the shaft 10 at 16 to wind around a pulley 18 for linkage with the removal device's operating lever 20, as at 22 (FIG. 5 a, operating lever 20 open; FIG. 5 b, operating lever closed). A first mounting plate 24 secures the operating lever 20 to the outside of the shaft 20 near its upper end, while a second mounting plate 26 secures the pulley with the top of the shaft 10 with the main cable 14 traversing the pulley 18 to couple with the operating lever 20. As shown in FIG. 1 (and more specifically at its Insert of FIG. 1 a) a 1 to 3 cable transition couples with the main cable 14 at the spring terminal B. With the shaft 10, for example, being of Schedule 40 aluminum of 1.25″ outside diameter, a main cable 14 of 3/16″ diameter transposes into three narrower diameter cables 30, 32, 34—each of ⅛″ diameter. As shown in FIG. 1, the three cables 30, 32, 34 extend along through the right most end of the shaft 10, to exit at what will be the bottom end of the cobble removal device 36. The top end of the shaft 38 is where the pulley 18 is secured, it being understood that in use, the cobble removal device of FIG. 1 would, in effect, be rotated 90° clockwise from the orientation depicted. (FIGS. 2 and 3 more clearly show the cables 30, 32 and 34 extending through the bottom end of the shaft 36 than can be seen in the 2-dimensional view of FIG. 1 where, by the very nature of the drawings, one cable is blocked from view.)

As FIG. 1, and more clearly FIGS. 2, 3 and 4 illustrate, the cobble removal device also includes three prongs each secured by a mounting plate 46 adjacent the bottom end 36 of the shaft in 120° spaced apart relation. As FIGS. 2, 3 and 4 show, the cables 30, 32 and 34 exit through the bottom end 36 to link and secure to an underside of the prongs 40, 42 and 44. In a preferred embodiment of the invention, each prong is fabricated of ⅝″ diameter aluminum, each with pin or like gripper sleeves 48 and holding pins 50. As FIGS. 2, 3 and 4 also show, the cobble/small boulder removal device of the invention further includes three extension springs 52, 54, 56, respectively linking each prong to the exterior of the shaft 10, as by means of hook and eye fasteners 58, 60. The cables 30, 32 and 34 similarly link to the inside of the prongs 40, 42, 44 by hook and eye fasteners 62, 64.

With the component arrangement of FIG. 2 and FIG. 5 a illustrating the appearance of the cobble removal device when it is first inserted downwardly, bottom-end 36 first, and with FIGS. 3, 4 and 5 b showing the component arrangement when a rock or small boulder is encountered to be removed from a borehole, the removal device of the invention essentially consists of a quiescently open 3-prong claw with a series of springs and cables within or affixed to a shaft to draw the prongs closer together by closing the operating lever to then grip and hold rocks or small boulders encountered in the drilling to then be lifted away and dropped via a manual release of its operating lever when the shaft is pulled back upwardly along the borehole manually by an operator of the removal device.

Specifically, the schematic arrangement of FIG. 1 illustrates a quiescent open condition of the cobble removal device as it is to be lowered into the borehole to remove the cobbles. The 3-prong claw is initially open. Upon reaching the rock or small boulder to be removed, the user would rotate the operating lever 20 clockwise, in the direction towards the shaft 10 in stretching the main cable 14 along the pulley 16, against the tension of the spring 12, to pull together the prong cables 30, 32 and 34 against the tension of the extension springs 52, 54, 56. The rotation of the operating lever 20 in this manner is as shown going from the view of FIG. 5 a to the view of FIG. 5 b, and serves to close the prongs 40, 42, 44 in going from the view of FIG. 2 to that of the views of FIGS. 3 and 4. With the grippers 48 and holding pins 50 then grasping the cobble, the shaft and the tool can be lifted out from a borehole and away, with a relaxing of the operating lever 20 then enabling the tension of the springs 12, 52, 54 and 56 to rotate the claw back to its quiescent condition of FIGS. 1 and 2 in releasing the rock or small boulder.

While there has been described what is considered to be a preferred embodiment of the present invention, it will be readily appreciated by those skilled in the art that modifications can be made without departing from the scope of the teachings herein. For at least such reasons, therefore, resort should be had to the claims appended hereto for a true understanding of the scope of the invention. 

1. A cobble/small boulder debris removal device in borehole excavating comprising: a hollow shaft, a quiescently open 3-prong claw secured at a bottom end of the shaft, and a series of springs and cables within or affixed to the shaft to close the prongs to then grip and hold rocks or small boulders encountered in the drilling of a borehole to be then removed by their being lifted away and released via a manual relaxation of a lever connected to a main actuating cable traversing through the shaft.
 2. A cobble/small boulder debris removal device in borehole excavating comprising: a quiescently open 3-prong claw; a shaft enclosing first, second and third cables, each individually connected at one end with one prong of said 3-prong claw; first, second and third springs, each individually connecting one of said prongs to angularly spaced locations on an external surface of said shaft; a one-to-three cable transition coupler within said shaft having an input connected to a first end of a fourth spring within said shaft and an output connected to respective second ends of said first, second and third cables; an operating lever secured to an outside of said shaft; and a fourth cable connecting said operating lever to a second end of said fourth spring; whereby user rotation of said operating lever in a first direction pulls upon said fourth cable to close said claw and whereby user relaxation of said operating lever releases said fourth cable to return said claw to its quiescently open condition.
 3. The cobble/small boulder debris removal device of claim 2 wherein said first, second and third springs individually connect one of said prongs to 120° spaced locations on an external surface of said shaft.
 4. The cobble/small boulder debris removal device of claim 3, also including grasping and holding means on each of said prongs in securing debris to be removed.
 5. The cobble/small boulder debris removal device of claim 4 wherein said cables are fabricated of steel.
 6. The cobble/small boulder debris removal device of claim 5 wherein said fourth cable is fabricated of steel of a 3/16″ diameter and wherein each of said first, second and third cables are fabricated of ⅛″ diameter steel.
 7. The cobble/small boulder debris removal device of claim 6 wherein each of said prongs are fabricated of aluminum.
 8. The cobble/small boulder debris removal device of claim 7 wherein said shaft is of a length 5-10 feet.
 9. The cobble/small boulder debris removal device of claim 8 wherein said shaft is of cylindrical construction of an outside diameter of 1.25 inches.
 10. The cobble/small boulder debris removal device of claim 8 wherein said operating lever is of a length of 16 inches.
 11. The cobble/small boulder debris removal device of claim 7, also including a pulley around which said fourth cable is wound in connecting said operating lever to said second end of said fourth spring. 